Four-cycle internal-combustion engine



C. A. HULT.

FOUR-CYCLE INTERNAL COMBUSTION ENGINE. APPLICATION man SEPT. 9. 1919.

1,389,873. PatentedSept. 6, 1921.

3 SHEETS-SHEET l.

A woz-Jay C. A. HULT.

FOUR-CYCLE INTERNAL COMBUSTION ENGINE. APPLICATION FILED SEPT. 9. 1919.

Patented Sept. 6, 1921.

3 SHEETSSHEET 2.

C. A. HULT.

FOUR-CYCLE INTERNAL COMBUSTION ENGINE. APPLICATION FILED SEPT. 9, 1919.

Patented Sept. 6, 1921.

3 SHEETS-SHEET 3.

Inventar CJHu/L, .By

dwoz'lzey the explosive gas mixture Awill thus be com UNITED STATES CARL Annu: Herr,- or 'sr'.ocxao'nm, SWEDEN.

FOUR-CYCLE INTERNAL-COMBUSTION ENGINE.

Specication ol` Letters Patent. Patented Sept, 6, 1921.

Application led September 9, 19.16. Serial No. 322,754.

To all whom, t may concern: l

Be it known that I, CARL ALRIK Huur, a subject of the King of Sweden, and resldent of Torsgatan 4', Stockholm, in the Kingdom of Sweden, have invented certain new and useful Improvements in Four-Cycle Internal-Combustion Engines, for which I have filed an application' for patent in Sweden, Oct. 20, 1916; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable vothers skilled in the art to which it appertains to make and use the same, reference being -had to thel accompanying drawing, and to figures marked thereon which form a part of this specification. In internal combustion engines of the common four cycle type it is usual to have all the strokes of the pistons of the samelengths during the different operations oi expansion, exhaust, suction arid compression-and this can not be otherwise, when ,common *crank shafts are used to transmit the` motions of the pistons.

By the-equal lengths of the strokes during the cycle the diii'erent operations are limited to work in a way that is by no means correct, if a good result of the'heat units spent to run the engine is to. be attained.

In the exhaust stroke, the burnt gases will not be driven out entirely, but a greatV per cent. will'remain in the -cylinder after the stroke is done and then mix with the fresh gases, sucked in during the following stroke. In a benzin motor where the ratio of compression generally is not above four to one posed of about 25 percent. already burnt exhaust gas and 7 5 per cent.l ,fresh gas, the whole constituting a bad explosive. gas which occupies 25%mo1'e room than otherwise would be needed. The walls of the room in the cylinder containing the compressed gas mixture will,'consequently, be a great deal larger than otherwise would be necessary, andas about 45% of the heat units from the explosions escape through the Awalls of the cylinder and the greatest per cent. thereof, from the walls of the chamber of compression, a proportional saving of heat units would be attained, if the room of compression was limited to contain only the pure gas mixture.

`the expansion stroke.

Theoretically the best way to obtain a good result of the exploded gases in an en- .gine of four cycle type would be to drive the burnt gases out of the cylinder entirely,

by running the piston up the entire length of the cylinder and then to give the suction .stroke such a limited length thatl only so much pure gas would be admitted that could be entlrely, or nearly so, expanded during It would further be the best way not to ignite the gases during the last period of compression, as is now done, but let the ignition take place first different strokes of the pistons are regulated, so that the operations practically come very near to the theoretically best way of running such an engine.

To obtain these results the pistons work in combination with curved tracks shaped in such 'a way that, during the exhaust stroke, the pistons are 'brought to run up at the entire length of the cylinder and at the'suction stroke run outward only long enough to take in as much pure gas as can be almost expanded duringthe. stroke of expansion.

During the compression stroke, the pistons are given such lengths of stroke as to cause a suitable compression to the charge reduced to pure gas. At the end of this stroke the pistons will he brought to -a standstill, or nearly so, during a period of time corresponding to the time, in which the electric ignitionof the gases takes place. The

.next stroke, in which the exploded gases expand is given such a length .compared to the suction stroke, that the expansion comes very near to the atmospheric line and the burnt gases escape withoutthe usual noise. In order to get full atmospheric pressure of the gases, at the beginning of the compression stroke, the suction stroke works in combination with the centrifugal force, to fill the engine cylinder, this being'caused by letting the cylinders rotate around a central hollow shaft, through whlch the fresh gases are admitted on their way to the cyllnders.

The improvements are shown on the annexed drawing wherein Figure 1 shows an engine in longitudinal section along the broken sectional ,line a-b-o 1n Flg. 2, of which the section above the line a-b 1s lshown above the central line in Fig: 1, showing the position of a cylinder andits piston at the end of the exhaust stroke, together with the part of the cam tracks that belongs to that stroke, andthe section on the right hand side along the line b-c is show n below the central line in Fig. 1, showing a cylinder and its pistons at the end of the expansion stroke and the portion of the cam track that belongs to that stroke.v Flg. 2 shows the engine in transversal section.

Figs. 4 and 5 show details of the water' jacket which contains the different cylinders. Fig. 3 Vshows the different curves of the track, that regulates the different op'- erations and strokesv of the pistons.

,1 designates the engine shaft. 2 and 3 the ball bearings thereof. 4 the inlet pipe for thev fresh gases. 5 the opening in the same that regulates the inlet. 6 are the cylinders.l 7 the pistons. 8 thewrollers connected to the pistons. 9 are the annular tracks on which the rollers run. 10 are the exhaust valves. 11 the rollers actuatingv the valves. 12 the cam track which actuates the valve rollers. 13 are the channels leading .from the inlet pipe to the cylinders. 14 are the spark plugs and 15 is a ringuniting the spark plugs. 16 is the cable leadin the electric sparks from. a magneto or the llke. 17 are openings in the cyl- 1, and each of these cylinders has two pis' inders, from whence the exhaust gases escape. 18 are circular flanges of the W'ater Jacket which hold the cylinders vin their position, as they areclamped together with an annular ring 19 by means of bolts 20. 21 is the outside casing of the vmotor and 22 'an opening in said casing, through which the exhaust `gases and'water. may'escape. 23 are rollers 'united to theA pistons and 24 are stationary camsv or guides on which said rollers are actuating, during the suction stroke. 25 is a pipe for cooling-water and 26 a liner. leading the water through holes 27 into an annular space'28, outside of the inlet pipe, to holes 29, from whence the water is thrown into vthe water jacket. 30 inv Fig. 3 shows the shape of curve of the ann ular track for theperiod of expansion, 31 for the period of exhaust, 32 for the period of suction, 33 for the period of compression, and 34 for'the period of ignition.

The engine shown in Figs. 1 to 5 has four open cylinders 6 placed parallel to the shaft tons 7 working'to and from each other at an equal distance from the.transversal center of the cylinder. The rooms of suction, com- Vtons drive the kwhich latter, by the rotatlon o between the closed ends of the pistons and then ignited by the spark plug the expansion takes place, forcing the two with the rollers 8 outward. The rollers 8 1n the pistons run at the tmeon,v the' v part .30 of thetrack 9. The pressure ,from the explosion, on 'thefpistons and rollers, forces the latter torun, down to'theI deepest point of the track, thereby actuating the cylinders to move sidewis'e and thus to rotate about one fourth of arevolution around the center of the motor shaft 1. At a certain period before-the en d of the outward motions of the pistons, the openings 17 in the cylinder are uncovered by the former andthe burnt exhaust gases escape out into the caslng 21 of the motor and then through theghole 22. But at the same time as the openings 17 begin'to uncover by. the pistons, on their Way outward, the valve l0 actuated by the cam roller 11 and the cam track 12, opens, leaving a fr ae passage' for the air to run .1n through the channel 13 and into the cyl1nder. The cam track 12 is so shaped as to kee the valve l() open during the whole period of the time, during which the pistons, on their way outwarda-nd inward, keep the apertures 17 open and then still further until the piston cans on their return stroke of exhaust have met at the middle ofthe cylinder by means of the rollers and the part 31 of the track. y

By letting'the exhaust gases out through the openings 17 no heated exhaust gases w1ll have to go throu h thevalve 10, but instead of this, the resh 'air actuated by the centrifugal forcecaused b the rotation of the motor will run throng the valve opening into the motor cylinder and out through the openings 17, thereby causing the room in the cylinder to be cooled and swept completely free from all -burnt exhaust gases. On their return stroke of exhaust, the pisfresh air remaining in the cylinder out throu h wthe valve opening 10, t ereby causing a urthercleanin vandcoollng of the ycylindenj"-'lWhen the pistons gulded and actuated by therollers 8, part 32 of the track 9, rollers 23 and guides or tracks 24 are on their next stroke outward, the valve 10 actuated by the spring 35 'closes icq and pure gas mixture is sucked in through the inlet pipe 4 and the openin the motor,

5 in same,

has just come in position to communicate with the opening or channel 13 running out into the cylinder. The part 32 of the track 9, which regulates the suction stroke, is so vshaped as to limit the length of stroke and thereby the quantity of gas sucked in,ito a portion as large as can be expanded,orl

nearly' expanded, during the expansion strok y f By this shortened stroke the openings 17 are notuncovered4 and the charge of gases is kept. in the cylinder for the next return stroke in which it vis compressed. During the suction stroke, when the cylinder vhas been in open communication -with theiinlet" pipe for gas mixture 4, the centrifugal force l caused by the rotation of the motor` cylinders, has, in combination with the suction caused by the outward movements of the pistons, also caused the cylinder to.be entirely filled with gas mixture at the: atmos' pheric pressure. The rotation ofthe motor causes the opening 5 of the inlet pipe to be automatically closed at the end of the suction stroke. 1

In the returnlstroke of the g-pistons, the rollers 8 meanwhile running on the parts 33 of the tracks 9, the gas mixture is suitably compressed, whichoperation is now limited to compress pure gases only, whereby the room ot compression can be kept about 25 per cent. smaller than otherwise would be necessary. t y

Vhen the compression is fully complete the ignition takes place, while the rollers run over the parts'34 of the tracks 9. .TheseY parts of the tracks may run at equidistance from the transversal center of the cylindersA the explosion to work before the compres'-Y sion is complete and thus it doesnot work to repress the inward movements of thepistons during that period, as' in common motors.

The cycle described works naturally all the cylinders in the same lway, and if four cyhnders are used, as shown 1n the drawing, one stroke of expansion, exhaust,

suction and compression will always be under operation dui-lng the same time,by one of the different cylinders, as there are four curves on the track 9. actuating the' different pistons. rlfhe strokes of expansion will thus succeed one anothenso that the impulse of rotation given therefrom will be continual duringfthe' whole of la revolution, causing a steady Vand equal running without the aid of a heavy fiy wheel.

.The weight of the rotating parts, inclu` sive the water in the water j acket, is quite sufficient to equalize the fluctuation of the pressure on the pistons.

The cylinders4 are preferably cooled by water, although even air may be used Jfor that purpose. The water is led by the pipe 25 into the sleeve 26 and out through the holes 27. The water is ,thus caught by the rotating hollow shaftoutside of the inlet pipeand thrown by holes 29 out in the. water jacket Which surrounds the cylinders. By meansof the centrifugal force the water will, while the motor runs, stand in the water jacket in equal distance from the center of the motor shaft. When the water jacket has been filled in to the central openings of its Walls 18, the water led in afterward will run over the edges of these central openings and be thrown out in the casing, wherefrom it may run out from the opening 22.

The ring that unites thespark plugs is naturally constructed from electrically noul conducting material, so that the electric spark does not run over from one plug to another, but each plug receives an electric spark in the right moment from the sliding contact between the plugs and the electrocable 16.

V,By adapting open cylinders placed parallelly and symmetrically and of equal 'weights around a common shaft and causing the 'pistons to work two and two in each Cylinder' in symmetrical movements, at equidistance from the transversal center ot the `cylinders and actuating two annular tracks of equal constructions, the engine can be Ina-de to run ata great speed with a complete running balance.

-The Water jacket is so constructed that it also serves to unite and hold the cylinders together andin the right position around the shaft. The anges 18 of the water jacket have openings 36, in which the cylinders lare fitted, and the latter have flanges f 37 which are clamped tightly together to the flanges .18 by'means of the bolts 20.

The annular cam tracks may naturally be provided'. with more than five curves and still work in the mannerdescribed, although with the .difference that, if ten, fifteen. twenty or twenty-five curves are provided, the whole cycle will be done in one half,

lone third, one fourth or one fifth of a revolution of the engine shaft..

It is not essential to the invention to have-- the cylinders placed in the way described and shown in the drawing, open at both ends. with two pistons in each cylinder, actuating two cam tracks, by means of rollers, but the contrivance whereby different and suitably regulated lengths of the different piston strokes in the cycle are obtained, so as to practically reach the theoretically best way of working the different operations of expansion, exhaust, suction, compression and ignition,in a four cycle motor, `is the main object aimed at. This is attained, even if the cylinders are closed at one end, asis most usual, with one piston in each cylinder, coperating'with one cam.track only, by means of a roller or otherwise by a sliding contact and even if the cylinders are situated in a radial direction to the engine shaft or are otherwisev inclined to the same,

or if the annular cam tracks, united to the Aengine shaft, rotate and the c linders are stationary, because the same regulated movements o'f the dierent piston strokes in the cycle, will be at hand in all cases. But

by the construction described and shown in the drawing, the engine is given a complete running bala-nce and Athe pressure in the cylinders, during the expansion and comi pression strokes, is equalized and balanced, so as not to give any end pressure to the engine shaft. Neither is it essential that the coperations 'between the pistons and the,

' cam tracks are done by means of rollers, as

yshown and described. These coperations can be done by other means, suchas sliding shoes orthe like, united to the pistons and sliding on rollers or balls, running on the y cam tracks in endless series.

During the strokes of expansion, exhaust and compression the gases inclosed between the 'pistons tend to keep the latter and their rollers pressed outward against-the curves of the cam tracks, but during the stroke of suction, the atmospheric pressure on the outside of the .pistons and the vacuum insideof the cylinder, caused by the suction, would,

1f not prevented, stop the outward move- .ments of the pistons. In order to prevent this and to give the pistons the outward movements needed, during that operation, the small rollers 23 united to the piston cans, run on the inner guides or tracks 12 formed in curves equal to the part 32 of the caml track 9.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is: v'

1. .In a four cycle internal combustion englne 1n combination, a plurality of cylinders placed symmetrically around and parallel to the engine shaft and open at both ends, two pistons in each cylinder, working to and from each other at the same time and at equidistance from the transversal center of the cylinder, each iston being provided with a roller or the llke, two annular tracks placed concentrically around the engine shaft against which the piston and rollers work, the rollers running on the annular tracks and coperating with curves so long stroke of expansion, one still longer strokel of exhaust, one short stroke of suction, one still shorter stroke of compression and one slight movement at the time of ignition, during at least one turn of the engine shaft, openings (17) for the exhaust gases, so placed in the cylinders as to be automatically uncovered -by the pistons near the end of the expansion stroke, valves (10) coperating with said openings, leaving a free passage for the air to sweep through the cylinders during a part of the expansionand exhaust strokes, a cam track (9) actuating the valves (10) by means of the rollers (8), a guide or cam track (12) guiding the outward stroke of suction, by means of the rollers (23), an inlet pipe '(4) for the gas mixture with an opening (5), channels (13) leading from the inlet pipe to the cylinders, spark plugs situated in said channels, a ring (15) composed of electrically non-conducting materialand uniting the spark plugs, and an electric cable v(16) sliding on said ring.

2. In a four cycle internal combustion engine in combination, a plurality of cylinders placed symmetrically around and parallel to the engine shaft' and open at both ends, two pistons in each cylinder, working to and from each other at the .same time and at equidistance from the transversal center of the cylinder, each piston being provided with a roller or the like, two curved annular tracks plaeedconcentrically around the en? yshaped as to actuate and guide the in and outward movements of each piston can, into one long stroke of expansion, one still longer stroke of exhaust, one short stroke of suction, one still shorter stroke of compression and one slight movement at the time of ignition, during at least one turn of the engine shaft, openings (17) for the exhaust gases, sol placed in the cylinders as to be automatically uncovered bythe pistons near the end of the expansion stroke, Valves (10) coperating with said openings, leaving a free passage for the air to swee through the cylinders during a part of t e expansion and exhaust strokes, a cam track (9)2 actuating the Valves (10) by means of the rollers (8), av guide track (12) guiding the outward stroke of suction, means of the b rollers (23), an inlet pipe (il) for the gas two flanges (18) kept together by bolts (20), circular openings (36) 1n said langes, corresponding to the outside diameter of the cylinders, and in which the cylinders are tted and kept in position around the shaft, flanges (37) on the cylinders, tightening against the flanges (18) 'of the Water jacket and by Which the cylinders are kept in their .the Water jacket by means of the centrifugal force.

In Witness whereof, l have hereunto signed my name. v

CARL ALRIK HULT. 

